Coded record method and apparatus

ABSTRACT

Coded record manufacture and apparatus suitable for storing digital representations of graphical images, such as characters, are disclosed herein for use in subsequent reproduction of the images, as on the face of a cathode-ray tube. Images or characters are scanned to obtain electrical signals indicative of the features thereof and the signals are recorded as digital representations.

O United States Patent 1151 3,644,903 Kolb et al. Feb. 22, 1972 [541 CODED RECORD METHOD AND [56] References Cited APPARATUS UNITED STATES PATENTS [72] lnventors: Edwin R. Kolb; John F. Blaha, both of Cleveland; Webster C. Roberts, south 3,495,216 2/1970 S1lverschotz "340/149 Euchd of Ohm Primary Examiner-Terrell W. Fears [73] Assignee: Harris-Intertype Corporation, Cleveland, Attorney-Y0unt and Tarolli Ohio 22 Filed: June 17, 1970 1 ABSTRACT 1 Coded record manufacture and apparatus suitable for storing [21] Appl' 46900 digital representations of graphical images, such as characters, w are disclosed herein for use in subsequent reproduction of the Related U.S. Apphcamn Dam images, as on the face of a cathode-ray tube. Images or Division Of 1966, characters are scanned to obtain electrical signals indicative of the features thereof and the signals are recorded as digital representations. [52] U.S. Cl. ..340/173 R, 101/426, 340/1463,

346/1, 340/173 LM 6 Claims, 7 Drawlng Figures [51] Int. Cl ..Gllc 13/04 [58] Field of Search ..346/l; 340/1463, 173 R, 172.5;

PATENTEDFEBZZ m2 FIGS SCHMITT SYCHMITT TRIGGER TRIGGER SHEET 2 OF 2 pp 88 TOGGLE "I -83 READER 90 72 75 R REGISTERS o $$Eb- 7 READER JCONTROL -98 INVERTERS k -9/ TAPE 95 READER I j 6'/ 66 FEED DELETE sToP CODE DETECTOR DETEcToR DETEcToR 1: I 96 I 97 L A 5 g OP 84 89 ST R Tv FIG'T LOGIC I 831 as Q b 0 A 0- 5 J L 1 as 1 9/ To TAPE 90 FROM TAPE 98 READER READER REsET CONTROL CODED RECORD METHOD AND APPARATUS This is a division of our copending application, Ser. No. 591.734. filed on Nov. 3, 1966, now US Pat. No. 3,588,870 and assigned to the same assignee.

This invention relates to coded records and the manufacture thereof with the records being suitable for use in reproducing characters and images, as with the use of a cathode-ray tube in a photosetting machine.

There are commercial phototypesetting machines now available which can set type in various sizes, according to printing measurements, from four to 72 points, in column widths up to 72 picas, and at speeds of at least characters per second. The 'quality of the product of machines of this type, which is either a negative or positive produced on aphotographic film or a positive produced on photographic paper, is considered to be in all respects comparable to the type set by conventional hot metal or typecasting machines.

Such phototypesetting systems employ high speed flash. photography and photograph an entire character at a time, usually by projecting a flash beam oflight through a stencil or equivalent to shape the beam to the shape of the character. This beam passes through various types of optical systems to increase or decrease its size as desired. In between the exposure of the individual characters, relative movement is caused between the projection system and the photographic film to produce the desired space for the individual characters and for the spaces between words to make up justified lines of type. Due to the precision requirements in timing the flashes of light and control of the spacing movement, it is believed that phototypesetting systems of the projection type will be incapable of substantial increases in speed, although this is by no means a certainty, and the present invention constitutes another approach to phototypesetting, which by its very nature, is capable ofa much higher character production rate.

The present invention em loys a character generator member, such as a disc, drum or tape, onto which is optically recorded digital information capable of reproducing a selected character on a portion of the cathode-ray tube display face. The character generator member is constructed by recording on a photographic surface the digital information obtained from scanning an optical font of characters which have been converted into av digital form. The character generating member, therefore, contains sufficient digital information to reproduce the digitized character on the display face of the tube.

It is an object of this invention to provide a character generator wherein a font of characters is stored in digital form and includes sufficient information to reproduce completely a character on the face of a cathode-ray tube and wherein a character generator also provides information as to the width of each character.

It is another object of this invention to provide a method and apparatus for converting a font of characters into a digitized form for recording on an optical disc for subsequent reproduction on the face of a cathode-ray tube as required by a coded control record.

These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings:

FIG. 1 is a flow chart showing the digitation of the letter A, the conversion of the digitized letter to a paper tape and the recording of the letter onto a character disc;

FIG. 2 is a view of the digitized letter A;

FIG. 3 is a detailed drawing of the digitized letter A showing the scanning pattern;

FIG. 4 is a detail view of a portion of the paper tape produced by the apparatus when scanning a digitized letter;

FIG. 5 is a detail view of a portion of the character disc showing a track containing the digitized letter recorded thereon along with control information;

FIG. 6 is a block diagram of the encoder generator control for placing on the character disc the digitized letter; and, 7

FIG. 7 is a detail schematic diagram of the encoder generator correction control circuit.

} CHARACTER ENCODING Referring now to the drawings, which show a preferred embodiment of this invention, and particularly FIGS. 1 through 5, a method and apparatus employed for converting a basic letter or symbol into a coded signal are shown. This signal may be placed in a digital memory device such as a photographic character generator disc, drum or tape for later use in the production of characters on the face of a cathode-ray tube.

The character generator member thus created will thereafter form a significant portion of the character generation system to be later described.

The basic character or symbol 10, as shown at A in FIG. I is first digitized, or converted into a form usable in the character generator member, by placing the letter on an analyzing grid 11, shown at B in FIG. 1. The letter may then be digitized either manually or by a computer so that the digitized form of the letter 12 (shown at C in FIGS. 1 and 2) conforms to the blocks of a graph. The letter is thus converted from an analog form into a digital form having an appearance closely resembling that of the original letter.

The digitized character 12 is then placed on the scanner mechanism 15 shown at D in FIG. 1 which comprises a transparent drum 16 having a light positioned internally and provided with a photocell 17 adapted to scan the digitized character. The drum 16 may be rotated by a stepping motor 18 in incremental steps such that the digitized letter is moved an amount equal to one space on the graph for each electrical pulse applied to the motor 18. The photocell 17 is slidably mounted on a guide bar 19 and is driven by a cord 20 reeved on an idler pulley 21 at one end and a driving reel 22 at the other end. The driving reel is connected to a second stepping motor 23 which causes the photocell to move in incremental steps, each step corresponding to one block of the graph forming the digitized character. The photocell is positioned in the center of each graph block after each incremental step.

The output of the photocell is directed through an amplifier which controls a paper tape punching mechanism. Thus a reel of paper tape 26 is provided at the side of the scanner mechanism 15 and supplies the tape 27 through the punching mechanism 28. For each incremental movement of the photocell to the left (in the upper direction with respect to the character being analyzed), the paper tape will be punched with a hole in a channel which will hereafter be designated as the up channel. Likewise, for each incremental movement of the photocell to the right, corresponding to the downward scanning motion with respect to the character, a hole will be punched in the paper tape in another channel hereafter designated as the down channel. Each time the photocell scans an opaque area representing a part of the character being digitized, a hole will be punched in the paper tape in that channel reserved for that specific character. Thus, a paper tape, a detail of which is shown in FIG. 4, will contain an up channel 30, a down channel 31, and a channel 32 reserved for the character being digitized.

In this description, only one character is shown being recorded in digital form on the paper tape. It is to be understood, however,- that more than one character may be recorded on the same tape so long as the up channel and the down channel for each character are of identical length, and synchronized. In that way, only one set of up-down informa tion will be required for the several characters which may be recorded on a single tape.

Referring now to FIGS. 2 and 3, where the scanning sequence for the letter A is shown, the photocell first moves upwardly in a series of steps controlled by motor 23 until it has scanned all of the available blocks in the first vertical row on the left. Once the first row has been completely scanned, the motor 18, controlling the horizontal movement of the digitized character 12, is then pulsed one step to cause the punched in that channel reserved for the character on the paper tape. Thus, the characters will be scanned in a rastertype pattern. An end of character" (EOC) signal is provided at the lower right-hand portion of the block in the last vertical row which contains character information. In this form of the invention, the end of character block 37 (FIG. 3) may be either on a row which is scanned upwardly or downwardly, depending on the width information which is to be assigned to the particular character being recorded. While this end of character signal will not be printed or displayed by the cathode-ray tube, it will be used to activate certain control circuits in the phototypesetting system as will be described in detail later.

Once a digitized character has been completely scanned and a paper tape produced therefrom, the tape 27 will be placed on a reading machine 40, as shown at E in FIG. 1. The tape is scanned and the information contained therein ultimately placed on a character generator disc 41. This character generator disc 41 consists of a photographic plate mounted on a spindle 42 and driven by a motor 43 (FIG. 6). A set of bands on the disc 41 contain both control information and character information for use in the phototypesetting machine. In one embodiment of this invention l2 bands are included on each character generator disc 41, and each band contains a total of 35 tracks of information. A portion of one band of information is shown in FIG. 5. One track ofinformation, for example 41a is used to represent the up-down information, another track 41b is used as a fiducial channel to indicate the beginning of the character information, while another track 410 is used to record the synchronizing pulses obtained from a master character disc, and 32 tracks 41d in each band are used to record the character information stored on the paper tape. It can be seen therefore that, as a partical matter, more than one character would be recorded on a disc at the same time, and it is for this reason that several characters are recorded on a single paper tape at one time.

The particular manner in which the information stored on the paper tape is transferred onto the character disc is shown in FIGS. 6 and 7. A master disc 45 is mounted on a common shaft or spindle 42 with the undeveloped photographic plate 41 which is to become the character generator disc. The master disc 45has two channels of equally spaced marks, channel 46 containing 215 equally spaced marks which will be used as the synchronization pulses, and a set of marks 47 which divide the character disc into four equal quadrants. A source of light 50 is provided on one side of the transparent master disc 45 while four photomultiplier tubes 51 are spaced at intervals around the master disc and focused on the channel 46 containing the synchronization marks. The photomultiplier tubes 51 are all connected to a common buss 52 and function to average the signals received from the disc so that a single synchronization pulse is applied to a voltage sensitive pulse forming circuit such as a Schmitt trigger 53. A fifth photomultiplier tube 54 is focused on the channel 47 containing the quadrant marks and the output of this photomultiplier tube is applied to the pulse forming circuit or Schmitt trigger 55.

The synchronizing marks contained on channel 46 on the master disc will be placed directly onto the undeveloped character generator disc 41 by applying the output of Schmitt trigger 53 directly through line 57 to one of the glow modulator tubes 60. In the apparatus shown in FIG. 6, only nine glow modulator tubes are shown, but it is to be understood that a greater or lesser number of glow modulator tubes may be pro vided. One glow modulator tube will cause a single track to be applied to the undeveloped photographic emulsion on the character generator disc 41, and the creation of the character generator disc, which may be necessary to cause several of the operations described below to occur before a complete disc is created. The light output from each of the glow modulator tubes 60 may be focusedby means of lenses 61 onto a fiber optic light transmitting means 62. The output of Schmitt trigger 53 will also be applied to one of the inputs of AND- gate 65. i

The information recorded on the paper tape 27 is sensed by a tape reader 66 contained within the reading machine 40. The information stored on the tape may then be transferred to the character generator disc 41 in the following manner. Pushbutton 67 is momentarily closed and will cause the multivibrator or flip-flop 68 to set and thus apply an enabling output through line 69 to AND-gate 70. It will be noticed that the output from Schmitt trigger is applied along line 71 to gate so that, on the occurrence of a quadrant pulse from the Schmitt trigger 55, the AND-gate 70 will supply a triggering voltage through inverter 72 to set the flip-flop 73 in the quadrant counter and apply an enabling signal on line 74 to the AND-gate 65. The multivibrator or flip-flop 75 is also set at this time to hold the enabling voltage on line 74 to the AND-gate 65. With AND-gate 65 provided with an enabling signal on line 74, each synchronizing pulse sensed by the photomultiplier tubes 51 will cause a pulse to be applied through line 57 to the AND-gate 65 to trigger the single shot pulse circuit 76.

A set of registers or storage multivibrators are connected directly to the output of the tape reader 66 through inverters 81 by way of cable 82. The information stored on the tape will then be applied to the input of the registers 80 and will be recorded thereon at the time a toggle pulse is received from the single shot 76. At this time, the selected glow modulator tube 60 will cause light to be focused onto the charger generator disc at the selected locations.

A pulse from AND-gate 65 will also be applied through line 83 into the correction control circuit 84 each time a synchronizing pulse is detected by the photomultiplier tubes 51. As shown in detail in FIG. 7, the correction control system consists of a pair of step command counting flip-flops 85 and 86 and a sprocket counting pair of flip-flops 87 and 88. The sprocket counting flip-flop has its input connected by line to a feed detecting means in the tape reader 66 and has a pulse applied to it on line 90 each time a sprocket or feed hole in the paper tape 27 passes under the detector. The input 83 from the AND-gate 65 is applied to toggle flip-flop 85. The output of this flip-flop is tied to flip-flop 86 as well as to one of the inputs to the output gates 89. In like manner, the outputs ofeach of flip-flops 87 and 88 are also connected to the output gates 89 in the manner shown.

It is the function of the correction control circuit 84 to control the operation of the tape advancing mechanism to insure that the tape advances at the same rate as synchronizing pulses occur on the master disc 45. Therefore, an output will be applied from the correction control circuit on line 91 to cause the tape reader control 92 to advance the tape one position at the time a synchronizing pulse is obtained on input line 83. Once the tape has advanced, and a signal applied on line 90 into the input of flip-flop 87, the tape advance signal is 1 removed from line 91 and the tape will stop. Therefore, as

long as the sprocket counter flip-flops and the step command counter flip-flops are synchronized, the tape will remain in synchronization with the mater control disc.

The correction control circuit 84 also provides that if the paper tape 27 is behind, the sprocket counter circuits 87 and 88 will permit an output to be applied to the tape reader control 92 until synchronization is again obtained. On the other hand, if the paper tape has advanced one step too far, no output will be permitted on line 91 to the tape reader control until the sprocket command counter has sensed the required number of pulses coming in on line 83. In other words, the correction control circuit corrects for errors of plus or minus one step.

Also connected to the cable 82, which carries the information recorded on the tape, are control circuits 95, 96 and 97. which detect the occurrence of certain tape control functions. For example, detector 95 detects the occurrence of a feed signal on the tape which causes the tape reader control to advance until the feed code or codes have been eliminated. In like manner, the delete code detector 96 will also cause the tape reader control to advance the tape without the recordation of that information onto the character generator disc 41. A stop code detect 97 is also provided to terminate the operation of all of the circuits shown in FIG. 6. Thus, when a stop code is detected, a reset signal will be applied on line 98 to reset the flip-flops in the correction control circuit 84, the reader registers 80, and the flip-flop 75.

Once the master disc 45 has completed one revolution, the quadrant counter, consisting of flip-flops 73 and 99, will cause a reset pulse to be applied to the flip-flop 68, thereby removing the enable signal on line 69 to the AND-gate 70 and thereafter prevent further pulses from being applied through AND-gate 65 to the correction control system. Therefore, no further toggle pulses will be applied to the reader register and the tape 27 will cease to pass through the reader register. This is necessary in order to prevent double exposure of the character generator disc 41.

While it has been shown in this embodiment that the information on the tape will be applied to the unexposed character disc four times before the circuit is disabled, it is contemplated that in other embodiments of this invention, the number of times that a particular band of information may be applied to the disc will depend upon the amount of information required to be contained in that band. Therefore, some bands may be divided 20 times, for example.

After the disc 41 has been exposed and the desired number of bands have been placed thereon, which may require that the disc be exposed several times although at different locations, the photosensitive surface will be developed in the conventional manner to make a permanent record of the marks which have been applied thereto and will thereafter be utilized as the master character generator disc in the phototypesetting system.

We claim:

1. A process for storing characters for subsequent reproduction on the face of a cathode-ray tube typesetting apparatus comprising the steps of;

initially providing an optical font of characters to be recorded;

converting each of said characters in said font into digital form by dividing each of the characters into a plurality of discrete incremental units of approximately equal size;

scanning each of said converted characters to produce electrical signals representing the location of each of said incremental units with respect to the other incremental units forming that particular character;

and recording said signals to provide a reproducible digital record of each individual character in the font.

2. The process defined in claim 1 wherein the recording step includes first producing a low density record of the incremental units, then converting said low density record into a high density permanent record from which the incremental units for reproducing any selected character can be recalled.

3. The process defined in claim 1 wherein the recording step includes photographically producing a permanent optical record of all the incremental units of each character in said font.

4. The process defined in claim 3 wherein the step of producing a permanent optical record is performed by recording the incremental units for each single character in separate circular tracks on a rotatable member, and recording all the incremental units for producing a single character several times in its unique track together with a signal indicating each beginning of the information for producing the corresponding character.

5. The process defined in claim 2 wherein a separate low density record is formed for each character, and a plurality of low density records are converted simultaneously into a high density permanent record.

6. The process defined in claim 2 wherein the step of producing the low density records includes recording signals identifying the scanning motion in which the scanning step is performed, and the recording of incremental units for a plurality of characters is synchronized with common signals identifying the scanning motion to minimize the number of signals recorded for identifying scanning motion. 

1. A process for storing characters for subsequent reprodUction on the face of a cathode-ray tube typesetting apparatus comprising the steps of; initially providing an optical font of characters to be recorded; converting each of said characters in said font into digital form by dividing each of the characters into a plurality of discrete incremental units of approximately equal size; scanning each of said converted characters to produce electrical signals representing the location of each of said incremental units with respect to the other incremental units forming that particular character; and recording said signals to provide a reproducible digital record of each individual character in the font.
 2. The process defined in claim 1 wherein the recording step includes first producing a low density record of the incremental units, then converting said low density record into a high density permanent record from which the incremental units for reproducing any selected character can be recalled.
 3. The process defined in claim 1 wherein the recording step includes photographically producing a permanent optical record of all the incremental units of each character in said font.
 4. The process defined in claim 3 wherein the step of producing a permanent optical record is performed by recording the incremental units for each single character in separate circular tracks on a rotatable member, and recording all the incremental units for producing a single character several times in its unique track together with a signal indicating each beginning of the information for producing the corresponding character.
 5. The process defined in claim 2 wherein a separate low density record is formed for each character, and a plurality of low density records are converted simultaneously into a high density permanent record.
 6. The process defined in claim 2 wherein the step of producing the low density records includes recording signals identifying the scanning motion in which the scanning step is performed, and the recording of incremental units for a plurality of characters is synchronized with common signals identifying the scanning motion to minimize the number of signals recorded for identifying scanning motion. 